package demo1;

import java.util.ArrayList;
import java.util.Scanner;

public class Test4 {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        while (input.hasNextLine()) {
            String s = input.nextLine();
            if (s == null || s.length() == 0) {
                return;
            } else if (s.length() > 100) {
                return;
            }
            int[] upCase = new int[26];
            int[] loCase = new int[26];
            StringBuilder stringBuilder = new StringBuilder();
            for (int j = 0; j < s.length(); j++) {
                if (isCase(s.charAt(j)) == 1) {  //判断是不是小写
                    loCase[s.charAt(j) - 97]++;
                    if (loCase[s.charAt(j) - 97] == 1) {
                        stringBuilder.append(s.charAt(j));
                    }
                } else {
                    upCase[s.charAt(j) - 65]++;
                    if (upCase[s.charAt(j) - 65] == 1) {
                        stringBuilder.append(s.charAt(j));
                    }
                }
            }
            System.out.println(stringBuilder.toString());
        }
    }

    public static void main1(String[] args) {
        String s = "asdfasdfghas";
        int[] upCase = new int[26];
        int[] loCase = new int[26];
        StringBuilder stringBuilder = new StringBuilder();
       // ArrayList<Character> arrayList = new ArrayList<>();
       // int i = 0;
       /* while (i < s.length()) {
            arrayList.add(s.charAt(i++));
        }*/
        for (int j = 0; j < s.length(); j++) {
            if (isCase(s.charAt(j)) == 1) {  //判断是不是小写
                loCase[s.charAt(j) - 97]++;
                if (loCase[s.charAt(j) - 97] == 1) {
                    stringBuilder.append(s.charAt(j));
                }
            } else {
                upCase[s.charAt(j) - 65]++;
                if (upCase[s.charAt(j) - 65] == 1) {
                    stringBuilder.append(s.charAt(j));
                }
            }
        }
        System.out.println(stringBuilder.toString());

    }
    public static int isCase(char ch) {
        if (ch >= 'a' && ch <= 'z') {
            return 1;
        }
        return -1;
    }
}
